To create bottle neck by extruding outwards all faces normally?
You can extrude along vertex normals to do that. AltE then 'Region (vertex normals)'



edit if previous version does not has this extrusion mode:


Remove the ring, for instance CtrlR then X
Extrude and scale and only on X and Y: E (extrude) s (scale) and ShiftZ (only along X and Y)
Then CtrlE, bridge the loop